With recent progress in communication technology, services offered by communication network operators to the subscribers thereto have also gained more attention. Among such services, so-called location based services (LCS) find considerable attention. For example, a subscriber may have subscribed to a service providing the subscriber with up-to-date traffic information via the network to his communication terminal. To this end, however, in order to provide the proper information to the subscriber, it is inevitable to know the subscriber's location within the network. Stated in other words, a subscriber currently being located in the Berlin area does not need to receive traffic information concerning the Helsinki area.
As mentioned above, the present invention is concerned to provide such location information on the location of a terminal attached to a communication network.
In this connection, it has to be noted that the present invention as subsequently described is applicable to any communication network as long as terminals may change their position within the communication network. Thus, the network may support the use of e.g. mobile terminals in the sense of wireless terminals or even some kind of “fixed” (i.e. non-wireless) terminals which may however be connected (“plugged-in”) at different locations within the network. The expression terminal as used herein is intended to cover any such type of subscriber equipment. Likewise, also the communication network as such is not limited to a certain type of communication network. For purposes of describing the present invention, however, the subsequent description refers to a WCDMA (WCDMA=Wideband Code Divisional Multiple Access) radio communication network also known as 3G UMTS (3G=3rd generation, UMTS=Universal Mobile Telecommunication System) network. Nevertheless, other communication networks based on other or similar transmission principles are also suitable for the present invention being implemented thereto.
FIG. 1 shows a typical example of at least those parts of the communication network architecture which are involved when the present invention is implemented to the communication network. The illustrated example in FIG. 1 refers to the 3G UMTS network architecture.
As shown, a terminal also known as user equipment UE is adapted to communicate via the network. Note that for communication the user equipment UE has at least to be registered to the network in a subscriber database and attached to a communication network. “Attached” here means a state of the user equipment in which it is switched on and it is known to the network that the user equipment UE terminal is (in principle) “ready” for communication even if currently idling.
In communication, the user equipment accesses the network infrastructure via an air interface (not expressly shown).
More precisely, the terminal UE exchanges signals with a radio transceiver device referred to as Node_B (in UMTS) (corresponding to Base Station BS in GSM). Each Node_B has a certain coverage area within which communication with the Node_B is enabled. The coverage area is also referred to as a cell. Each cell is identified by at least a cell identifier. Optionally, a cell identifier CI can be supplemented by a location area identifier LAI. The entire communication network area is thus composed of a plurality of cells. The location of Node_B's is defined upon network planning. Thus, a network management/planning system functional entity has a knowledge of the network topology and also of the cell identifiers corresponding to the respective Node_B's.
A group of Node_B's are controlled by a radio network controller RNC (corresponding to base station controller BSC in GSM). Of course, although not shown in FIG. 1, more than one RNC can be present in the network depending on its size/area covered. In order to keep the illustration simple, however, only one RNC has been shown. Note that a RNC represents an access control entity of said network, which is currently in charge of controlling access of said terminal to said network.
Further, one or more RNC's are grouped for being controlled by a mobile services switching center MSC (3G-MSC) serving as a routing entity currently in charge of routing messages for said terminal. This means that the MSC switches calls/connections concerning a terminal of interest in that the MSC “selects” the proper RNC controlling the proper Node_B via which the terminal communicates. Depending on the size of the network, of course more than one MSC are present. A moving and/or roaming terminal may thus be present in the area of a MSC which may also be referred to as visited MSC VMSC.
Note that in 3G UMTS networks not only speech (as an example of real-time data) are transmitted, but also packet data (as an example on non-real-time data) are transmitted. Packet data transmission takes place via a so-called GPRS network existing “in parallel” and comprising SGSN (Serving GPRS Support Node) and GGSN (Gateway GSN) nodes. In the GPRS, the SGSN corresponds in functionality and hierarchical location within the network to the VMSC explained above.
Connected to the MSC/SGSN is on one hand a location determination functional entity SMLC which is in turn connected to a gateway entity GMLC (Gateway Mobile Location Center) and on the other hand the network planning/management system mentioned earlier above.
The GMLC has a connection to a subscriber register HLR (Home Location register) and/or HSS (Home Subscriber Server) keeping a record of subscribers having subscribed to the network and the services available to them. In addition, the GMLC provides for a gateway functionality offering a connection to the “outside” of the network, where an application (e.g. run on a computer device) is located. (The application may be associated to a service control point entity SCP of the network (not shown).)
Signaling between GMLC—SMLC and SMLC—MSC/SGSN is achieved using MAP3/SS7 (Mobile Application Part 3/Signaling System No. 7), as shown in FIG. 1.
So far, the network architecture has roughly been described in order to simplify understanding of the invention. Of course, the entities described above may perform additional functions as compared to those briefly highlighted above. However, a full description of the capabilities and interrelations there between can not be given in the framework of the present patent application. Rather, the reader is referred to the corresponding standards published by 3GPP (3rd Generation Partnership Project) and/or ETSI (European Telecommunication Standards Institute).
Now, when requiring location information related to a specified terminal, according to an earlier solution, a so-called CAMEL ATI request was issued from the GMLC (triggered by the application requiring the location information). (CAMEL=Customized Application for Mobile network Enhanced Logic, ATI=Any Time Interrogation). According to this procedure, the GMLC sends an ATI request to the HLR which forwards the request message as “Provide Subscriber Info” to the MSC. In the response message, cell identity CI is returned to the GMLC via HLR. This CI has to be transferred into coordinates, e.g. position calculation capability to GMLC, i.e. an operator proprietary interface between GMLC and SMLC has to be provided for.
However, an operator/manufacturer specific interface between SMLC and GMLC reduces interconnectivity of such entities if provided by different manufacturers.
In a further approach, the applicant of the present invention conceived to fetch network parameters from the base station controller BSC and/or radio network controller RNC using location based services LCS standard messages. (Note that with Camel ATI mentioned earlier above only Cell ID or SAI can be fetched from MSC/SGSN.) These parameters fetched are CI (Cell Identity) and TA (Timing Advance) and Rx-levels (received signal levels) and Service area Identity SAI (in 3G). The terminal position calculation entity provisioned in connection with the MSC and referred to as SMLC calculates the user position estimate based on these parameters.
Although this example procedure relates to 2G (2nd generation) functionality, it does not restrict the invention to these procedures only. When implementing a terminal position calculation function in connection to the MSC, in this concept the GMLC requests the user position from visited MSC, i.e. VMSC. The VMSC forwards the request further to the BSC which responds with Cell ID, Timing Advance and power level information (CI+TA+Rx−levels). The MSC forwards these parameters to the calculation functional entity, i.e. the SMLC entity. After position calculation, the SMLC sends the coordinate information to the GMLC which sends them further to the LCS application having requested for the location information.
In rough outline, this procedure is for example disclosed in “Nokia mPosition for Legacy Phones”, by M. Lankinen, page 7, retrieved under http://www.radiolinja.fi/inenglish/mcatch/radiolinja.pdf from the Internet on Nov. 15, 2001.
Now the problem is that the BSC and/or RNC from which the parameters are requested is specifically required to be adapted to the system functionality. If the BSC/RNC has for example been manufactured by another manufacturer and/or for another network operator, it is not able to respond to the LCS request with mentioned parameters. Thus, the whole procedure would fail.
This in turn would lead to the fact that location based services would not be available in those locations in which the BSC/RNC in charge is not adapted to the above outlined implementation.